This project consists of multiple interrelated studies designed to test the use of 11C-labeled compounds in diagnostic nuclear medicine. Having identified various agents as potential 11C-labeled radiopharmaceuticals for the detection of cancer and the imaging of various organs, methods are devised to synthesize and purify such agents. Following preclinical tests of these materials in animals, they are then tested in humans. Using 14C as a label for 11C we have devised rapid techniques (approximately 1 hr) for the synthesis and purification of 11C-labeled 1-aminocyclopentanecarboxylic acid (ACPC), a potential cancer detection agent, and for DL-tryptophan, DL-valine and DL-leucine, potential pancreas imaging agents. Clinical studies of 11C-ACPC as a tumor-localizing agent are now in progress. First results have been promising. Cak Ridge National Laboratory's 86-inch proton cyclotron is used to produce the 11C activity used for labeling this agent. Clinically useful 11C-labeled preparations of the other three agents (for pancreas visualization) will be made available in the coming year. In further developmental studies we will attempt to devise methods for the synthesis of 11C-labeled estradiol (breast cancer and adrenal visualization). We will also carry out preliminary tests in animals of various alpha substituted alpha amino acids (similar to ACPC) as possible tumor-localizing agents that may be superior to ACPC.